Alkaloids. Substances of a vegeta-ble origin, analogous to the alkaline bases, in which the medicinal activity of the plants in which they are found appear to reside. (Cooley.) Among the natural organic bases, or alkaloids, the following are the principal, as enumerated by Professor Fownes.

3997. Morphine or Morphia

3997.    Morphine or Morphia. This is the chief active principle of opium. The morphia of commerce is a white crystalline powder; but when crystallized in alcohol, forms brilliant, prismatic, transparent, and colorless crystals, which turn nitric acid red. In powder, unlike strychnine, it is fusible without decomposition, and strongly decomposes iodic acid. It is insoluble in ether, scarcely soluble in water, and freely soluble in alcohol. Potassa and ammonia precipitate morphia from the solutions of its salts.

3998. To Find the Percentage of Morphia in Opium

3998.      To Find the Percentage of Morphia in Opium. An excellent process for ascertaining the quality of opium is to boil an infusion of 100 grains opium with 25 grains quicklime, made into a milk with water; to filter while hot, saturate with a dilute hydrochloric acid, and to precipitate the morphia by ammonia. After expelling any excess of ammonia by heat, the precipitate is collected, dried, and weighed; the weight in grains will nearly represent the percentage of morphia in the opium.

3999. Narcotine

3999.     Narcotine. An alkaloid found in the insoluble portion of opium, and forms small, colorless, brilliant crystals, which give to nitric acid an orange tint.

4000. Codeine, or Codeia

4000.     Codeine, or Codeia. Obtained from hydrochlorate of morphia, in colorless, transparent, eight-sided crystals, which do not color nitric acid red.

4001. Thebaine, or Paramorphine

4001.      Thebaine, or Paramorphine. This is also obtained from opium in colorless needles like those of narcotine. It does not color nitric acid red, and is much less soluble in water than codeine.

4002. Cinchonine, or Cinchonia

4002.    Cinchonine, or Cinchonia. This is the active principle of Peruvian bark, contained in the largest quantity in the pale bark. It crystallizes in small, brilliant, transparent, four-sided prisms, insoluble in ether. Cin-chonicine and cinchonidine are other varieties of this alkaloid.

4003. Quinine, or Quinia

4003. Quinine, or Quinia. This is also obtained from Peruvian bark, being found in largest quantity in the yellow variety of the bark. It crystallizes in small white needles. It may be distinguished from cinchonine by the form of its crystals, and its solubility in ether.

4004. Quinoidine, or Amorphous Quinine

4004.   Quinoidine, or Amorphous Quinine, is a yellow or brown resinous mass, identical in composition with quinine. Quinicine and quinidine are also varieties of quinine. (See Nos. 4025 (Quinometry), etc..)